var Base64 = {
	// private property
	_keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
	// public method for encoding
	encode: function(input) {
	  var output = "";
	  var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
	  var i = 0;
	  input = Base64._utf8_encode(input);
  
	  while (i < input.length) {
  
		chr1 = input.charCodeAt(i++);
		chr2 = input.charCodeAt(i++);
		chr3 = input.charCodeAt(i++);
  
		enc1 = chr1 >> 2;
		enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
		enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
		enc4 = chr3 & 63;
  
		if (isNaN(chr2)) {
		  enc3 = enc4 = 64;
		} else if (isNaN(chr3)) {
		  enc4 = 64;
		}
  
		output = output + this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) + this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
  
	  }
  
	  return output;
	},
  
	// public method for decoding
	decode: function(input) {
	  var output = "";
	  var chr1, chr2, chr3;
	  var enc1, enc2, enc3, enc4;
	  var i = 0;
  
	  input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
  
	  while (i < input.length) {
  
		enc1 = this._keyStr.indexOf(input.charAt(i++));
		enc2 = this._keyStr.indexOf(input.charAt(i++));
		enc3 = this._keyStr.indexOf(input.charAt(i++));
		enc4 = this._keyStr.indexOf(input.charAt(i++));
  
		chr1 = (enc1 << 2) | (enc2 >> 4);
		chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
		chr3 = ((enc3 & 3) << 6) | enc4;
  
		output = output + String.fromCharCode(chr1);
  
		if (enc3 != 64) {
		  output = output + String.fromCharCode(chr2);
		}
		if (enc4 != 64) {
		  output = output + String.fromCharCode(chr3);
		}
  
	  }
  
	  output = Base64._utf8_decode(output);
  
	  return output;
	},
  
	// private method for UTF-8 encoding
	_utf8_encode: function(string) {
	  string = string.replace(/\r\n/g, "\n");
	  var utftext = "";
  
	  for (var n = 0; n < string.length; n++) {
  
		var c = string.charCodeAt(n);
  
		if (c < 128) {
		  utftext += String.fromCharCode(c);
		} else if ((c > 127) && (c < 2048)) {
		  utftext += String.fromCharCode((c >> 6) | 192);
		  utftext += String.fromCharCode((c & 63) | 128);
		} else {
		  utftext += String.fromCharCode((c >> 12) | 224);
		  utftext += String.fromCharCode(((c >> 6) & 63) | 128);
		  utftext += String.fromCharCode((c & 63) | 128);
		}
  
	  }
  
	  return utftext;
	},
  
	// private method for UTF-8 decoding
	_utf8_decode: function(utftext) {
	  var string = "";
	  var i = 0;
	  var c = 0;
	  var c1 = 0;
	  var c2 = 0;
  
	  while (i < utftext.length) {
  
		c = utftext.charCodeAt(i);
  
		if (c < 128) {
		  string += String.fromCharCode(c);
		  i++;
		} else if ((c > 191) && (c < 224)) {
		  c2 = utftext.charCodeAt(i + 1);
		  string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
		  i += 2;
		} else {
		  c2 = utftext.charCodeAt(i + 1);
		  c3 = utftext.charCodeAt(i + 2);
		  string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
		  i += 3;
		}
  
	  }
  
	  return string;
	}
  }
  
  module.exports = Base64